Not necessarily. There is a hormone that causes your joints to loosen and your bones tend to move and pop from this. I'm on the 7th baby and the hormone kicks in really early for me like at 5 months or so. It's very uncomfortable. You can feel your pelvis cracking and popping all the time. Lower back pain is common that close to the end too. Until you start getting serious cramps or sharp pains I wouldn't worry about it. Plus you get alot of Muchas and discharge. Just take it easy so that you back pain will go away.